Exhaust header



United StatesPatent Marion L. Thompson Rolling Hills, California May 2 1, 1969 Dec. 8, 1970 Modern Tube Bending & Manufacturing Long Beach, California 72] Inventor [21 J Appl. No. [22] Filed [45 Patented [73 Assignee [54] EXHAUST HEADER 3 Claims, 3 Drawing Figs.

[52] U.S. Cl. 123/52; 60/29;123/56:181/33,181/35,18l/36,181/40- [51 Int. Cl. F02b 75/24; FOln 7/10; F0 2b 77/00 [50] Field ofSeerch 60/29, 32;

l23/52(M), 52(M2), l88( 1M), 56(Al 56(A2), 56(A), 56(A3);181/33.04, 40, 35.2, 36.4, 56;

282/(lnquired) [56] References Cited UNITED STATES PATENTS 2,862,490 12/1958 Trisler l23/52M 2,541,973 2/1951 Wiegman 60/29 2,649,083 8/1953 Vogel et al..... 60/32X 2,940,249 6/1960 Gospodar... 60/32 3,298,332 1/1967 Elsbett 123/52 FOREIGN PATENTS 506,100 10/1951 Belgium 181/364 440,955 1/1936 Great Britain.. 181/3304 1,511,976 12/1967 France 181/364 966,932 9/1957 Germany.... 60/29 1,151,697 7/1963 Germany 181/56 OTHER REFERENCES The Scientific Design of Exhaust and intake Systems by Philip H. Smith, G.T. Foulis & Co., LTD, London, December 1963. Pages 85,120, and 127 Primary Examiner--Wendell E. Burns AttorneyFulwider, Patton, Rieber, Lee & Utecht ABSTRACT: An exhaust header for connection with an internal combustion engine having first and second pairs of exhaust ports leading from sequentially firing cylinders, the first exhaust port of each pair being disposed forwardly on opposite sides of said engine and the second port of each pair being disposed rearwardly on said engine and on the respective sides opposite the first ports of the respective pairs. The exhaust header includes first and second pairs of exhaust conduits, the first conduit of each pair being connected with the respective first exhaust ports of each pair and extending rearwardly along opposite sides of the engine and connecting with the upstream end of horizontally arranged primary collectors disposed at the rear of the engine. The second conduits of each pair of conduits have their upstream ends connected with said second exhaust ports and crossover behind the engine to connect with the respective upstream ends of the respective primary collectors, the downstream ends of such primary collectors being joined to form a main collector. With this arrangement, the collective resistance provided by the respective flow paths defined by the exhaust conduits, primary collectors and main collector produce sufficient pressure drop to provide the desired back pressure at the respective exhaust ports and presents an uncluttered configuration for convenient installation without interference with other components on the engme.

EXHAUST HEADER BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of an exhaust header adapted for connection to the exhaust ports of an internal combustion engine.

2. Description of the Prior Art Conventional exhaust headers generally employ a manifold which is connected to the engine exhaust ports for comingling and carrying off the exhaust gases emanating from such ports. Exhaust header systems have been proposed which include pairs of individual exhaust conduits connected with exhaust ports of cylinders firing at equal time intervals and which join to form primary collectors which are themselves joined on their s downstream ends to form a main collector thereby providing a flow path which presents the necessary pressure drop for providing the desired back pressure at each of the exhaust ports. An exhaust header of this type is shown on Page 314 of the book entitled, The Design and Tuning of Competition Engines, new advanced edition by Phillip H. Smith. Engines having the exhaust ports of cylinders firing at equal time intervals disposed forwardly and rearwardly on the same side of the engine pose a problem for incorporation of an exhaust header of this type because the conduits leading from the rear ports are relatively short thereby failing to provide the necessary pressure drop for producing the desired back pressure at such rear exhaust ports.

SUMMARY OF THE INVENTION The exhaust header of present invention is particularly adapted for connection with an engine including pairs of exhaust ports of cylinders having equal firing intervals disposed forwardly and rearwardly on opposite sides thereof. The exhaust header includes a first pair of conduits connected with the ports of sequentially firing cylinders, the first conduit being connected with the forward port on one side of the engineand extending rearwardly therealong to connect with the upstream end of a first primary collector disposed at the rear of the engine and the second conduit connecting with the port disposed rearwardly at the opposite side of the engine, crossing over behind the engine, and also connected with the upstream end of such primary collector. A second pair of conduits are connected with a second pair of exhaust ports of sequentially firing cylinders, the first conduit of that pair connecting with a port disposed forwardly on the opposite side of said engine and extending rearwardly therealong and connecting with the upstream end of a second primary collector disposed at the rear of the engine and the second conduit of such second pair connecting with the exhaust port disposed rearwardly at said one side of the engine and crossing over to connect with the upstream end of said second primary collector. The collectors join at their downstream end and form a common collector whereby the flow paths defined by the respective conduits and collectors present sufficient resistance to provide the necessary pressure drop to maintain the desired back pressure at each of the exhaust ports.

The objects and advantages of the present invention will become apparent from a consideration of the following detailed description when taken in conjunction with the accompany accompanying drawing.

DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of an exhaust header embodying the present invention;

FIG. 2 is a bottom plan view of the exhaust header shown in FIG. 1; and

FIG. 3 is a diagrammatic view of the exhaust header shown in FIG. I.

DESCRIPTION OF THE PREFERRED EMBODIMENT The header of present invention is particularly adapted for connection with an opposed four cylinder engine, such as a Volkswagon engine lll shown in phantom in FIG. 1, including a first pair of exhaust ports 13 and 15 leading from sequentially firing cylinders and a second pair of exhaust ports 17 and 19 leading from a second pair of sequentially firing cylinders. Still referring to FIG. I, a first pair of exhaust conduits, generally designated 21 and 23, are connected with the respective ports 13 and 15, the first conduit 21 extending rearwardly along the near side of the engine and being connected at its rear extremity with the upstream end of a horizontally disposed primary collector, generally designated 27. The second conduit 23 of the first pair has its upstream end connected with the rearwardly disposed port 15 and crosses over behind the engine to also connect with the upstream end of the primary collector 27.

In a similar manner, a second pair of conduits, generally designated 31 and 33, have their upstream ends connected with the respective exhaust ports 17 and 19 of sequentially firing cylinders, the exhaust conduit 31 extending rearwardly along the far side of the engine, as viewed in FIG. 1, and having its rear extremity connected with the upstream end of a second primary collector, generally designated 37. The second conduit 33 of the second pair has its upstream end connected with the rearwardly disposed port 19 and crosses over behind the engine to also connect with the upstream end of the primary collector 37.

The collectors 27 and 37 are joined together at their downstream extremities and cooperate to form a main collector, generally designated 39. With this arrangement, the flow paths through the respective exhaust conduits 21, 23, 3! and 33 and the respective collectors 27 and 37 and common collector 39 present sufficient flow resistance to provide the necessary pressure drop to produce the desired back pressure at the respective exhaust ports 13, l5, l7 and 19 without the necessity of providing additional loops, bends or turns for the conduits 23 and 33 connected to the rearwardly disposed ports 15 and 19. An additional feature is that the scavanging effect produced by merger of the conduits 21 and 23 is partially isolated from the scavanging effect produced by merger of the conduits 31 and 33 to prevent compounding of the scavanging effect as would be the case if all four individual conduits were merged simultaneously into a common collector thereby exposing each exhaust steam to the scavanging effect of every other exhaust stream.

The forwardly disposed exhaust ports 13 and 17 open forwardly and the conduits 21 and 23 include respective bolt flanges 43 and 45 for connection to the engine block, the conduits then projecting forwardly and bending outwardly and downwardly to extend rearwardly along their respective sides of the engine. Referring to FIGS. 1 and 2, the rear extremity of each of the conduits 21 and 31 is formed by respective elbows 51 and 53 which turn inwardly to connect with the upstream ends of the respective collectors 27 and 37.

The rear ports 15 and 19 open rearwardly and the forward extremity of the respective conduits 23 and 33 are formed by respective elbows 57 and 59 which include respective bolt flanges 61 and 63 for securement to the engine block. The elbows 57 and 59 project rearwardly and turn outwardly to connect with respective turned back portions 65 and 67 which turn inwardly and project across behind the engine to connect with respective reversing portions 71 and 73 which continue the projection behind the engine and turn downwardly and reverse on themselves to connect with the respective upstream ends of the respective primary collectors 27 and 37.

As noted above, the primary collectors 27 and 37 are horizontally arranged at the rear of the engine and have their outer extremities forming Ys which define respective female ports 77, 79, 81 and 83 for receipt of the rear extremities of the respective conduits 21, 23, 31 and 33. The primary collectors 27 and 37 project inwardly across the rear of the engine and turn rearwardly and are joined to form the main collector 39. The adjacent walls of the turned back portions of the primary collectors 27 and 37 are cut out and such collectors are welded together at the peripheries of such cut outs. A bolt flange 91 is welded to the rear of the main collector 39 and mates with a bolt flange 93 of a conventional muffler assembly, generally designated 95.

In operation, the exhaust header of present invention may be conveniently installed on a stock engine by merely removing the stock-header system and bolting the new header in place. During operation of the engine, the exhaust from the port 13 will flow rearwardly in the exhaust conduit 21 and will experience a certain pressure drop. The exhaust from the port 15 will likewise flow through the conduit 23 crossing over behind the engine and will experience a pressure dropsimilar to that experienced in the conduit 21. The exhaust stream from these conduits 21 and 23 will be merged at the upstream end of the primary collector 27 and a certain amount of scavanging will take place. In a like manner, the exhaust streams through the conduits 31 and 33 will experience similar pressure drops and will be merged at the upstream end of the primary collector 37. The merged exhaust streams in the respective collectors 27 and 37 will then experience some pressure drop in these collectors and will be merged in the main collector 39 for expulsion to the atmosphere.

It is of particular importance that exhaust ports of sequentially firing cylinders are connected together at the upstream ends of the respective primary collectors 27 and 37 thereby enabling the exhaust conduits 21 and 23 from the rear ports to merely crossover behind the engine to provide the necessary length to produce the required pressure drop which will maintain the desired back p1 essure at the respective rear exhaust ports 15 and 19. Further, the scavunging effect produced by merger of the pairs of conduits 21. 23, 31 and 33 are spaced apart to avoid compounding of the resultant cumulative scavanging effect to prevent over scavanging and resultant reduction in engine performance.

From the foregoing, it will be apparent that applicant has provided a new and useful exhaust header which is straightforward in design and provides the required pressure drop for each of the respective exhaust conduits without excessive curvatures and bending thereof.

Various modifications and changes may be made with re- 4 gard to the foregoing detailed description without departing from the spirit of the invention.

lclaim:

1. An exhaust header for connection with a multicylinder engine having first and second exhaust ports leading from sequentially firing cylinders and disposed forwardly on one side of said engine and rearwardly on the opposite side of said engine, respectively, and third and fourth exhaust ports disposed forwardly on said opposite side and rearwardly on said one side, respectively, said header comprising:

a first pair of first and second conduits having their respective upstream ends adapted for connection with said first and second exhaust ports, said first conduit projecting rearwardly along said one side of said engine and said second conduit crossing over behind said engine;

a first primary collector having its upstream end connection with the downstream ends of said conduits;

a second pair of third and fourth conduits having their respective upstream ends adapted for connection with said respective third and fourth exhaust ports, said third conduit projecting rearwardly along said opposite side of said engine and said fourth conduit crossing over behind said engine;

a second primary collector having its upstream end connected with the downstream ends of said third and fourth conduits; and

a main collector having its upstream end connected with the downstream ends of said primary collectors whereby the exhaust flow path through said respective conduits and collectors present sufficient flow resistance to produce the necessary respective pressure drop to provide the desired back pressure at the respective exhaust ports and the scavanging effect produced by merger of the exhaust streams at the juncture of the first pair of conduits is partially isolated from the scavanging effect produced by merger of the second pair of conduits.

2. An exhaust header as set forth in claim 1 wherein said primary collectors are horizontally arranged at the rear of said engine.

3. An exhaust header as set forth in claim 1 wherein said primary collectors are joined together on their downstream extremities and cooperate to form said main collector. 

